1. Field of the Invention
The present invention relates to an improved data reproduction apparatus equipped with an automatic disk exchanger capable of automatically exchanging an optical disk with a different type or format of disk.
2. Description of Related Art
Numerous types of optical disks are presently available on the market as audio/video data recording media. For example, optical disks now available include the digital audio compact disk (hereinafter "CD") having a diameter of 8 cm or 12 cm, and the analog video laser disk (hereinafter "LD") having a diameter of 20 cm or 30 cm.
A plurality of sub-codes (channels P, Q, R to W) are recorded on a CD based on the CD format. Of these sub-codes, channel Q contains addresses, and an address always contains "1" for CDs (for example, "0001" in 4-bit data). A typical reproduction apparatus will have adjustment unit for determining what type of optimal disk is in the apparatus. Therefore, as the judgment unit of a reproduction apparatus detects "1" corresponding to channel Q, it can be determined that the optical disk set in the reproduction apparatus is a CD.
With regard to the LD, the determination is made on the basis of the size of the disk, with a sensor provided in the reproduction apparatus to detect whether or not the size of the disk set therein is larger than 12 cm (or if the diameter of the disk is 20 cm or larger). Since there is no CD which is larger than 12 cm in diameter, an LD can be identified by such a sensor.
In addition to the CD and LD, high-density video disk (hereinafter "DVD") capable of recording moving pictures and a plurality of voice data which are in accordance with the MPEG2 (Moving Picture Expert Group 2) standard has recently been developed.
A DVD is an optical disk having the same diameter as that of a CD, and appears similar thereto. The difference lies in whether it is an adhesion type or a single plate type and it is not easy for an inexperienced person to identify them from each other. Where the size of the DVD is 8 cm or 12 cm as with a CD, an inexperienced user may easily become confused as to which type of disk is set in the reproduction apparatus. In such a case, the user must take the disk out of the reproduction apparatus, and read the label of the disk to confirm whether it is a DVD or CD. After that, he or she must return the disk to the apparatus, and perform a necessary operation on the apparatus corresponding to the type of the disk, so as to start the reproduction. For a user, such work is very laborious.
As described above, recently, there are numerous types of disks having similar appearances, which are available in the market, and the users are required to purchase different reproduction apparatus for each type of disk.
Furthermore, using a plurality of reproduction apparatuses of different types is very inconvenient and also a heavy financial burden to have access to all the optical disk formats.
In one approach to overcome this problem, a device was developed which is capable of rendering a plurality of disks of the same type stand by in a disk storage
unit and retrieve, when disk selection data is provided, a disk corresponding to the selection data. In this device, the retrieved disk is automatically transferred to the disk drive unit of the reproduction apparatus, and set in the apparatus. After the disk is set, the apparatus starts to reproduce the contents of the disk. The above-described disk data reproduction apparatus is called a disk data reproduction apparatus or data reproduction apparatus having an automatic disk exchanger.
However, the conventional disk data reproduction apparatus and automatic disk exchanger entails a drawback in that it requires a great amount of time before the data of a disk is actually reproduced after the disk is exchanged.